Fluid-pressure brake.



PATBNTED APR. 23, 19027.

P. L. CLARK. FLUID PRESSURE BRAKE. APPLIUATION FILED JULY 14. 1904y 2SHEETS-SHEET 1,

PATENTED APR. 23, 1907.

P. L. CLARK. FLUID PRESSURE BRAKE.

APPLICATION FILED JULY 14. 1904.

2 SHEETS-SHEET 2V WTNESSES UNITED S'IAlllh PATEN T OFFICE.

FRANCIS L. CLARK, OF PITTSBURG,

PENNSYLVANIA, AssiGNoR To THE WESTINGHOUSE AIR BRAKE COMPANY, OFPI'IISBURG, PENNSYLVANIA. A CORPORATION OF PENNSYLVANIA.

FLUID-PRESSURE BRAKE.

Specification of Letters Patent.

Patented April 23, 190'?.

Application filed July 14,1904. Serial No. 216,628-

To @ZZ w/wm t may concern.-

Be it known that@ FRANCIS L. CLARK, a citizen of the UnitedStates,residing in Pittsburg, county of Allegheny, and State of Pennsylvania,have invented a certain new and useful Improvement in Fluid-PressureBrakes, of which the following is a specification.

This invention relates to fluid pressure 1o brakes and particularly tothe brake cylinder part oi the apparatus, the main object being tosecure ahigher and more eiiicient braking power with a less consumptionof compressed air or other fluid. l5 For this purpose the apparatuscomprises two brake cylinders, the first a small primary cylinder fortaking up the slack in the rigging i and perhaps applying the brakeshoes with a light or moderate pressure, and the secondary largecylinder into which the air cylinder pressure is admitted subsequentlyto the movement of the first brake piston and thereby greatly augmentsthe braking pressure with a slight movement of the second piston and theuse oi a correspondingly small amount of compressed air. The cylindersare preferably arranged in line with each other and provided withpistonsadapted to move i.: opposite directions and connected to 3G differentlevers of the brake rigging.

A certain amount et travel of the brake vpiston is ordinarily necessaryto take up slack and bring the brake shoes against the n wheels andwhere a single brake cylinder oi' a size suitable for heavy braking isemployed it is obvious that a large volume oi' air is required to vlillthe cylinder and apply the brakes with effective pressure. By the use ofthe small primary cylinder for taking up 1.0 thel slack and the largesecomlary cylinder for then reinforcing the pressure with which thebrake is applied, in accordance with this inventioinit will readily beapparent that the same degree of braking force may be 4,5 secured withthe use of a m'ucli smaller amount of compressed air. rlhe relative sizeof the cylinders may be varied to give any desired result and variousmeans may be employed forcontrolling the 5o admission of air to thesecond brake cylinder. Such means may be operated by the movement of thesmall brake piston or by the pressurelof the primary cylinder' or by thetriplel'lvalvefi,"device5 or in any other way desired.

l/Vhere the brake pistons act in opposite directions and are connectedup to different levers of the brake rigging some means must be employedfor locking the primary brake piston when it has completed its strokeand such locking device is preferably actuated by air pressure, althoughother locking mechanism maybe used, if desired.

In the accompanying drawings, Figure 1 is a longitudinal section of adouble brake cylinder and triple valve device constructed according tothe preferred form of my invention, in which the admission of air to thesecond brake cylinder is controlled by the triple valve, and a lockingdevice operated by air 7o pressure is employed for locking the primarybrake piston; Fig. 2 a sectional view of a portion of the triple valvedevice showing the parts in service position; Fig. 3 a similar Viewshowing the parts in lap position; Fig. 4 a plan view of the seat et thelmain slide valve of the' triple valve device Fig. 5 a face view of themain slide valve; Fig. 6 a face view of the small graduating slidevalve;l Fig. 7 a transverse section ole the locking mechanism taken onthe line w-:vw of Fig. 1; Fig. 8 a longitudinal sectional view show inga modification of my invention, and Fig. 9 a diagrammatic plan viewshowing one `form or' brake rig ring construction. 8 5

According to t 1e design shown in Fig. l, the small primary brakecylinder 1 and the large secondary brake cylinder i2, are formedintegral and contain their respective pistons 3 and 4 and rods 5 andwhich operate in 9o opposite directions.

- The triple valve device is preferably secured to the common pressurehead of the brake cylinders having a chamber 7 adapted to be connectedto the auxiliary reservoir in the usual way. As shown in the drawing the'triple valve device com rises the usual piston S, stem 9, main slide vave l() and graduating i slide valve l1l. In the main slide valve seatare located the vusual service port 12 leading to the first brakecylinder, quick action port 13 leading to the usual emergency piston,and exhaust port 14 leading to the atmosphere. In addition to 'thisordinary construction. there is provided a port 15 leading tothe largesecondary brake cylinder.

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rlhe main slide Valve .is provided with serv ice. or graduating port 16,emergency port 17, exhaust cavity 18 and additional port 1g, While thegraduati 5f slide Valve 11 has eavity 2Q for connecting ports 16` and 1Qof the main slide valve when the parts in release position shown in Fig. 1, or in lap position shown in 3. f

in order to hold the -irst brake pis ton and ro prevent it from beingforeed back when air isl admitted to the second hralre Cylinder, la

loelu'ng device may oe employed, and according to the torni ofnieeha-nisni shown iu Figs. l and. 7, this comprises oppositely locatedrows or inclined teeth 21 on the rod 5, two sliding jaws and. 23havingCorresponding ,teeth for engaging the rod, a wedge tor moving thejaws, a piston 25 and spring 2h located in Cylinder 27r`or actuating theWedge, the Cylinder communicating by ine-ans ot' a' port 28 with theport 15 and the second brake cylinder;- springs 2Qv may he employed `fornormally separating the 22 and 23 `l'or releasing the clampingmechanism.

A. pressure operated valve devise eoinprising piston 30 suhjeet to theopposing presot the i'irst hrale cylinder and an adjustable spring Simay also be used for inosing a valve 32 for Controlling a port 33 leadoing to the second brake cylinder.

ln order to insure the locking of the lirst Drake piston he'lore thelarg;A pist-on of the set-,ond brake cylinder noires the seeoni". pistonmay be provided w.. circular projet-ting ril) ln `e Sil aaien to heseated by the spring IE6 a ainf i met 35 when the piston is in rele :sepositioi., the 'ports oomtl e sereno l i kal i niuiiieating with ebwithin t rwli 'lar fe which is or a diam- .s to 'the primary H" thepiston 3 to tal'e ng and apol' wheels with more or o tu; size of the(zylinderriores lo lap posieomieits ports i suing eornz .u ,rein l,limiet to tl t'iroue'i ports n lf3 and 'if of the i ip-'frat xd l Y' I s'the p i Ii'ioves with secondari' loralio pistou 2, ton instantly moresthe wedge '26 und :uuatos the 22 and 22S to clamp )d 5, tlurehv loo jthe saine against movement. 'The air which was oon- ;l in the iirst hrwl, then exto the secon/ brake (grinder but, as

essere the 1Drake shoes are already hearing against the Wheels with somepressure, the movement of the soeoud hre-ke piston is Very slight,eensequently the volume to'be iilled. lof; the airis not rnueh greaterthan before while the pistou l which is now the effective one inexerting pressure upon the brake rigging h .a's a inuoh greater areathan the primary brake piston. The `braking pressure will therefore hegreatly increased with the saine Consumption ol air.

Referring to Fig. 9,' it Will be seen that when the rod 5 ot the firstbrake cylinder moves out thelever 38 is turned about its connection withrod 40 as a. iulerurn to exert a pull upon rod 4.1 to take up the sleekin the rigging and apply-the brakes, hut when rod 5 is elampedand therod 6 of the large piston moves out, the lever .39 aeting through rod 40turns lever about rod 5 as a lulerurn and thereby exerts additionalstress upon the rod 41 to apply the brake shoes with greater pressure.Aslaeli adjuster t2 may he conveniently applied`v to the stationaryfulcrum olE lever 3), ilj desired. W hen the brakes are released and thetriple Valve returns to release position, Fig. 1, the air from the firstbrake cylinder is discharged to the atmosphere through port 12j, cavity18 and exhaust port 14, While the air from the seoo'nil'hrake cylinderis 'released through port 15, cavity 1S and exhaust port The instantthat pressure is released from piston 25, the si ing 26 witlldrau's theweer. 24 and the jaws and 13 are released from the rod 5 hy the actionol: springs 2Q and also by the brake o t'linder spring 87 acting throughthe in-. olin'ed surfaces of the teeth 21. y

lt is not thought that the use ofthe projecting l lange .3ft and gasket35 will be necesy to insure the'inovement of the looking pistou inadvance of that of the second brake piston, hut il suoli eonstruetioneinployed it will he sein that-as the pressure is admitted to the secondbrake Cylinder and the loe-king Cylinder the area of the piston 4 whichis then subject to the pressure is only' slightly greater than that ofthe first brake piston 3, consequently,pressure at substantialiiY thesaine degree as obtained in the first hralae cylinder is admitted. tothe looking ovl-- inder and iston 2 5 before the second brake piston ismoved. As soon as the' flange 34 is nier/ed away from the gasket thefull hralring 'pressure obtained.

li' a continuous full servico application sl'iould hr made, that is, onein wliieli'the triple valve does not moveijbaolefroin service to lposition, the air under pressure ooninuos to l low into the Afirst brakecylinder u'npressure rises therein and upon piston.` a degree sufiioientto eompress the spring .'31, wliioh in ey .he for anyV desired amount,say lii'ty pounds ,per square inch. The ,valve 32 is then operated toopen the '.thesecond brake cylinder and the pressure locking cylinder,so that full braking power is obtained in either case.

yA'ccordin to the modification shown in Fi 8 the airl is supplied fromthe first'brake cyIinder to the second only through the valve deviceoperated by the first brake cylinder pressure, the valve being providedwith an additionalcavity 43 and exhaust port 44 for releasing air fromthe second brake cylinder to the atmosphere when the first brake cylin--der is released.

In this form of device the locking cylinder is connected directly to the`primary brake cylinder throu h a port 28',

and the piston 25 operates a c utch or block having teeth for engagingthe' teeth carried by the brake piston rod 5 for locking the same.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is l 1. In an air brake, the combination with aprimary brake cylinder and piston, anda secondary brake cylinder andpiston indepen dent of the first brake piston, of a fluid pressureoperated clutch or locking mechanism forone of the brake pistons. 2. Inan air brake, the combination with a l 4primary brake cylinder andpiston for operating a brake lever, of a secondary brake cylinder andpiston foroperating another brake lever, and a fluid pressure operatedclutch or locking mechanism for the primary `brake piston. 3. In an. airbrake, the combination of a lprimaryl ,brake cylinder ,and a secondaryrake cylinder in alinement with each other and having (pistons operatingin opposite directions, an a fluid pressure operated locking mechanismfor one of the brake pistons. 4. In an air brake, the combination With afrprimary brake c linder and. piston, of a secondary brake cy inder andpiston, means for supplying air from the primary brake cylinder to thesecond brake cylinder after the first piston has completed its strokeand a fiuid pressure operated locking'mechanism for the first brakepiston.

5. `In an air brake, the combination with a primary brake c linder andpiston, of a secondary brake cy inder and piston, and means operated vbybrake cylinder pressure for locking the first brake pleted its-stroke. l-V A 6l In an'air brake, the combination with a primary brake cylinderand a second brake cylinder 0f means operated b variations in train pipepressure for control ing the admission of airl from the. primary brakecylinder to the second brake cylinder. y 7. In an air brake, thecombination with a piston after it has'com- -primary brake cylinder anda second brake cylinder of a valve device operated by train pipepressure` for controlling the admission of air from the primary brakecylinder to the second brake cylinder.

cylinder, and triple valve device, o means operated by the triple valvedevice for controlling the admission' of air from the first brakecylinder to the second brake cylinder. 9. In an air brake, thecombination with a rimary brake cylinder and a secondary brake cylinderof' a triple valve device having ports for first admitting air to theprimary brake cylinder in service position and ports for establishingcommunication from the primary brake cylinder to the second brakecylinder in lap position.

10. In an air brake, the combination with a primarybrake cylinder, asecondar brake cy inder, and a pressure operated ocking mechanism forthe first brake cylinder, of a valve device operated by train pipepressure for controllin the admission of air from the first brake cyinder to the second brake cylinder and to thc locking mechanism.

11. In an air brake, the combination With a rimary brake cylinder, asecond ary brake cy inder, and a fluid pressure operated lockingmechanism, of means for sup lying air from the first brake cylinder to te second brake cylinder and to the locking mechanism after the firstbrake piston has completed its stroke.

12. In an air brake, the `combination with a primary brake cylinder, asecondar brake cy inder, and a pressure operated ocking mechanism,'ofmeans for su plying air from the first brake cylinder to tie secondbrake cylinder and to the locking mechanism after the first brake pistonhas com leted its stroke, and means for restrictin t e area of thesecond brake piston expose to air pressure before its outward movement.

13. In an air brake, the combination with a primary brake cylinder andpiston, of a secondary brake cylinderl and piston and a lockingmechanism comprising two oppositely movable clam s or jaws for. engagingone of the piston ro, s, and means subject to air pressure for operatingsaid clamps.

14: In an air brake, the combination with a primary brake piston havinoppositely 1ocated teeth, ofa secondary rake cylinder and piston, and alockingmechanism comprising two movable clamps or jaws for engaging theteeth of' the first piston rod, a wedge for actuating said jaws,and apiston subject to brake cylinder pressure for operatinU the Wedge.

lIn testimony whereof I have hereunto set my hand.

FRANCIS L. CLA RK.

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